%0 Journal Article
%A Cooper, Claire
%A Parthier, Daniel
%A Sibille, Jeremie
%A Tukker, Jan Johan
%A Tritsch, Nicolas
%A Schmitz, Dietmar
%T Ultraslow serotonin oscillations in the hippocampus delineate substates across NREM and waking.
%J eLife
%V 13
%@ 2050-084X
%C Cambridge
%I eLife Sciences Publications
%M DZNE-2025-00847
%P RP101105
%D 2025
%X Beyond the vast array of functional roles attributed to serotonin (5-HT) in the brain, changes in 5-HT levels have been shown to accompany changes in behavioral states, including WAKE, NREM, and REM sleep. Whether 5-HT dynamics at shorter time scales can be seen to delineate substates within these larger brain states remains an open question. Here, we performed simultaneous recordings of extracellular 5-HT using a recently developed G-Protein-Coupled Receptor-Activation-Based 5-HT sensor (GRAB5-HT3.0) and local field potential in the hippocampal CA1 of mice, which revealed the presence of prominent ultraslow (<0.05 Hz) 5-HT oscillations both during NREM and WAKE states. Interestingly, the phase of these ultraslow 5-HT oscillations was found to distinguish substates both within and across larger behavioral states. Hippocampal ripples occurred preferentially on the falling phase of ultraslow 5-HT oscillations during both NREM and WAKE, with higher power ripples concentrating near the peak specifically during NREM. By contrast, hippocampal-cortical coherence was strongest, and microarousals and intracranial EMG peaks were most prevalent during the rising phase in both wake and NREM. Overall, ultraslow 5-HT oscillations delineate substates within the larger behavioral states of NREM and WAKE, thus potentially temporally segregating internal memory consolidation processes from arousal-related functions.
%K Animals
%K Serotonin: metabolism
%K Wakefulness: physiology
%K Mice
%K Hippocampus: physiology
%K Male
%K Mice, Inbred C57BL
%K CA1 Region, Hippocampal: physiology
%K Sleep
%K behavioral state (Other)
%K hippocampus (Other)
%K mouse (Other)
%K neuroscience (Other)
%K oscillation (Other)
%K ripples (Other)
%K serotonin (Other)
%K Serotonin (NLM Chemicals)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:40643572
%2 pmc:PMC12252544
%R 10.7554/eLife.101105
%U https://pub.dzne.de/record/279880